JP2013503415A - Reliability testing of optical media using heat, humidity and light simultaneously - Google Patents

Abstract

A method and system for quickly evaluating the reliability of an optical medium is disclosed. It has been found that simultaneous exposure of an optical medium to heat, humidity, and light can test in a reasonable time to effectively differentiate a relatively stable medium from a relatively unstable medium.
[Selection] Figure 1

Description

  This application claims priority to US Provisional Patent Application No. 61 / 238,622, filed Aug. 31, 2009, which is incorporated herein by reference.

  Current industry standards for optical disc life testing were developed by Ecma International, a non-profit organization based in Geneva, Switzerland. For this standardization, the ECMA-379 1st edition was rapidly developed in August 2007, published with some modifications in ISO (ISO / IEC JTC1), and then approved as the ISO / IEC IS 10995 standard. This standard was published by ISO / IEC in April 2008. The second edition of the ECMA-379 standard published in December 2008, “Test Method for Estimate of the Archive Life of Optical Media” (a test method for estimating archive lifetime), is a published ISO / IEC standard IS 10995. Exactly the same as the first edition. This standard requires that a particular optical disc sample be tested for long periods of time under high temperature and high humidity stress conditions. The time of high temperature and humidity is at least 1000 hours (about 42 days), and these stress tests can extend up to 2500 hours (about 104 days or about 15 weeks). After being placed under the stress condition, the deterioration of the disc is detected in various ways.

  There are also standard test methods that measure for chemical degradation or coatings such as paint. For example, Xiahong Gu et al., "Linking Accelerate Laboratory Test with Outdoor Performance Results for Model Exposure Epoxy Coating System, High Acceleration Tests on Modeled Epoxy Coating Systems, H Disclosed is an accelerated test on an epoxy coating using simulated values (abbreviation for Simulated Photogradation via High Energy Radiant Exposure). Another disclosure regarding SPHERE is Chin, J. et al. W. Byrd, W .; E. , Embree, E .; Martin, J .; W. , And Tate, J .; D. “Ultraviolet Chambers Based on Integrating Spheres for Use in Artificial Weathering” (ultraviolet chamber based on integrated sphere for artificial exposure), J. Coat. Technol. 74, no. 929, p. 39 (2002), and Chin, J. et al. W. Byrd, W .; E. , Embree, E .; , And Martin, J .; W. "Integrating Sphere Sources for UV Exposure" (Integrated Sphere Source for UV Exposure), Service Life Prediction: Methodology and Metrology, Martin, J .; W. And Bauer, D .; (Eds.), Oxford Press, NY, p. 144, seen in 2001. As disclosed in these references, coating evaluation involves exposing the coating to light, high temperature, and humidity under control and measuring degradation products to assess chemical changes or degradation of the coating. Is done. In that case, irreversible chemical and physical changes in the bulk properties of the coating are measured. These tests differ from optical media tests that examine physical or chemical degradation in that the property being tested in the optical media test is data integrity or data retention. Changes that affect data integrity often differ from the chemical and physical indicators of the standard coating test. For example, a slight creep or a small amount of irreversible expansion or contraction is not important for coating evaluation and may be a physical change that cannot be measured. However, in optical storage media, even a 10 nm creep may cause irreversible data loss. Therefore, even if a small irreversible change occurs due to the environmental conditions to which the optical disc is exposed, the medium cannot hold data. Such changes that affect data retention are often not considered or measured in coating tests, and the changes measured in those tests are not clearly related to any changes related to data retention .

  Several patent documents and patents described below refer to tests and criteria for describing the quality of each optical disc. These patent documents and patents refer to exposure testing, and some refer to separate ISO standards.

  For example, US Patent Publication No. 2009/0135706 granted to Noguchi et al. On May 28, 2009 discloses the application of stress to an optical recording medium by exposure to xenon light having an illuminance of 40 klux for 50 hours. ing. Apart from that, Noguchi describes a storage test with medium standing at a temperature of 50 ° C. and a relative humidity of 80% for 800 hours (about 33 days).

  US Patent Publication No. 2008/0254252, granted to Watanabe on October 16, 2008, discloses a light fastness test for certain dye-based data materials, which includes a “merry-go-round” shaped light fastness tester. The medium containing the material is exposed to xenon light for 55 hours. Separate high temperature and high humidity stress tests are also performed on the same medium for 24 hours or 168 hours. Watanabe performed the 24 hour test at 60 ° C. and 90% relative humidity, but showed no temperature or humidity for the 168 hour test.

  In US Pat. No. 6,124,075 granted to Ishihara et al. On September 26, 2000, a laser ablated recording medium sample was held for 4 or 8 hours under a white fluorescent lamp having an intensity of 800 lux. The process to do is disclosed. Ishihara discloses a separate test in which the absorption spectrum of the sample is measured before and after exposure, the sample is kept in an environment of 60 ° C. and 70% relative humidity for 3 days, and then the change with respect to absorption is evaluated.

  US Pat. No. 5,939,163 granted to Ueno et al. On August 17, 1999 discloses a process of exposing an optical information recording medium to 40 klux xenon light irradiation for 720 hours (30 days). . A separate stress test included 720 hours (30 days) storage at 85 ° C. and 85% humidity. The effects are shown in tabular form and the results of each of these tests are listed in separate columns.

  U.S. Patent Publication No. 2006/0280066, published December 14, 2006, discloses a process of continuously irradiating light on an information storage disk prior to an accelerated test involving high temperature and high humidity. Subsequent accelerated tests hold the disc for 400 hours (about 17 days) at 85 ° C. and 85% relative humidity.

Miyazawa et al., U.S. Patent Publication No. 2007/0184386, published on August 9, 2007, tests light resistance by irradiating an optical recording medium with xenon lamp for 8 hours at 45 ° C. and 250 W / m ² . . The absorbance of the medium was measured before and after the exposure.

In US Pat. No. 6,368,692 granted to Yamazaki et al. On April 9, 2002, an initial reproduction signal was obtained and irradiated with a 1500 W metal halide lamp at an energy density of 30 mW / cm ² on the surface of the medium for 50 hours. A process for evaluating an optical storage medium by obtaining a reproduction signal is disclosed.

  US Pat. No. 7,507,524 granted to Satake et al. On Mar. 24, 2009 discloses an ISO standard specific to accelerated testing using light. This standard is designated as ISO-105-B02 in these references.

  It will be appreciated that there are many tests and variations thereof. Also, these tests change as the standards change over time. These changes suggest that various improved criteria are needed. However, the standards and tests generally appear to have not changed substantially over the years and only to that extent, and current industry standards and tests are still considered inadequate. Most of the tests disclosed herein have long exposure times, are extremely expensive to implement, and occupy test equipment for a long time. This long-term testing has made these assays impractical for developing or improving products. In addition, since it takes a long time to complete the test, consumers cannot use these test results when purchasing the product. In view of the above circumstances, there is a need for improvements in general-purpose accelerated tests that evaluate the degradation of optical information media under major environmental conditions and predict their quality.

  A method and system for quickly assessing the quality of an optical medium is disclosed. It has been found that by simultaneously exposing an optical medium to high heat, high humidity, and intense light, the reliability of the medium can be evaluated quickly and effectively. By determining the quality or error value of the media before and after exposure, the various media can be compared and the reliability and reliability of the media can be predicted.

  Simultaneous exposure to high heat, high humidity, and intense light also demonstrates a synergistic combination in this rapid and effective media assessment. When any one of these conditions is applied, the influence and effect of the other two conditions are emphasized. Thus, rapid and effective assessment becomes more difficult or impossible without simultaneous exposure to all three conditions of heat, humidity, and light.

Without being limited to any theory of action, it is believed that co-exposure provides the optimal combination of reaction conditions, reactants, and activators. Light, humidity, and heat are known activators or reactants for many chemical reactions, and examples of chemical reactions that do not occur within a reasonable period of time unless at least two of these activators are present. There are many. For example, the hydrolysis reaction clearly requires water. In addition, it is a well-known rule of thumb that the chemical reaction is accelerated about twice each time the reaction temperature increases by 10 ° C. Therefore, from 25 ° C. (room temperature) to 85 ° C., all chemical reactions will increase by 2 ⁶ = 64 times, which is a significant increase. Light, especially blue light or ultraviolet light, has a significant amount of energy, ie sufficient energy to break some chemical bonds. It can be said at least that exposure to ultraviolet light excites electrons to a higher energy state and increases the likelihood that the molecule will react with a reactant present nearby such as oxygen or water. The diffusion constant that determines the mobility of molecules increases exponentially (not linearly) with temperature. Therefore, as the temperature increases, the mobility of water and oxygen in the optical disk increases, ensuring the flow of these reactants to dyes and other materials activated by ultraviolet light in the disk. As described above, the simultaneous presence of high humidity, high heat, and intense light accelerates many chemical reactions, and also creates other chemical reaction possibilities, which are humidity, heat, and It seems that simply raising one or two of the light does not happen. These accelerated chemical reactions and new chemical reactions can significantly accelerate the damage or destruction of the material containing the dyes of the optical disc in particular, which allows a quick and effective evaluation.

FIG. 1 is a diagram showing a system for an acceleration test and evaluation of an optical medium. The system 12 can include one or more optical media 15, an environmental chamber 20, and an analysis device 40. The system can also include a graphic display device 45. The environmental chamber 20 may include a light source 25, a holding unit 30, and one or more spindles or holding mechanisms 35. FIG. 2 shows the PIE8-max values before and after various disks were exposed to heat, humidity, and light for 48 hours. The Y axis is PIE8-max and the X axis is a disk sample. The Y axis does not show a value higher than 3500. The shaded bar represents the initial value before exposure, the white bar represents the value after 24 hours exposure, and the black bar represents the value after 48 hours exposure. FIG. 3 shows PIE 8-average values before and after various disks were exposed to heat, humidity and light for 48 hours. The Y axis is PIE8-average and the X axis is a disk sample. The Y axis does not show a value higher than 3500. The shaded bar represents the initial value before exposure, the white bar represents the value after 24 hours exposure, and the black bar represents the value after 48 hours exposure. FIG. 4 shows the PIE 8-events values before and after various disks were exposed to heat, humidity, and light for 48 hours. The Y axis is PIE8-events and the X axis is a disk sample. The Y axis does not show a value higher than 4000. The shaded bar represents the initial value before exposure, the white bar represents the value after 24 hours exposure, and the black bar represents the value after 48 hours exposure. FIG. 5 shows PIE-max values before and after various disks were exposed to heat, humidity, and light for 48 hours. The Y axis is PIE-max and the X axis is a disk sample. The Y axis does not show a value higher than 300. The shaded bar represents the initial value before exposure, the white bar represents the value after 24 hours exposure, and the black bar represents the value after 48 hours exposure. FIG. 6 is a diagram showing PIE-average values before and after various disks were exposed to heat, humidity, and light for 48 hours. The Y axis is PIE-average and the X axis is a disk sample. The Y axis does not show a value higher than 200. The shaded bar represents the initial value before exposure, the white bar represents the value after 24 hours exposure, and the black bar represents the value after 48 hours exposure. FIG. 7 is a two-dimensional graph display of PIE8-max values relating to combinations of five optical media manufacturers and three DVD disk drive manufacturers. The Y axis does not show a value higher than 200.

Method for Evaluating Quality of Optical Medium One embodiment is directed to a method for evaluating the reliability of an optical medium. End users (end users) highly like the optical media to be durable, robust and reliable over the long term. Ideally, the optical medium should remain readable even after being stored under various conditions. Users typically store optical media under “reasonable” conditions, but the media is randomly exposed to “”. The method comprises exposing the optical medium to high heat, high humidity, and light simultaneously for a period of time.

  In one embodiment, the method comprises providing an optical medium, evaluating an initial quality of the optical medium, and exposing the optical medium to high heat, high humidity, and light simultaneously for a period of time. And evaluating the post-exposure quality of the optical medium. In general, the greater the heat, humidity, and light, the shorter the period for obtaining sufficient test results.

  The optical medium can generally be any type of optical medium used to store (save) digital data. Commonly used optical media include CD, DVD, and discs using Blu-ray technology. The optical medium to be evaluated may be a single optical medium or a plurality of optical media. It may be desirable to evaluate multiple articles in order to obtain a statistical index for evaluation. The plurality of articles may all be the same type of optical media or different types of optical media. For example, multiple disks with different lots and / or manufacturers may be evaluated to compare variations between lots or differences between manufacturers.

  Initial quality and post-exposure quality are generally determined using any numerical index or combination of numerical indices. An example of such a numerical index is to evaluate the error rate of an optical medium. Examples of error rates include block error rate (BLER), internal parity error (parity inner error: PIE), internal parity error 8 maximum value (PIE8 max, internal parity error total of 8 consecutive ECC blocks) ), Internal parity error 8 average value (PIE8 average, average value of total internal parity errors of 8 consecutive ECC blocks), internal parity error 8 event (PIE8 events, during analysis of optical media, PIE8 The number of times that the threshold value has been set or exceeded), PIF (parity inner failures, internal parity failure), PIF byte, and POF (parity outer failures, external parity failure). Another quality index is jitter. All these measurements are desirable as the value decreases. Any one of these measured values can be used or combined.

  The quality of the optical medium can be easily measured using various instruments such as Pulse Tech ODU1000 instrument (Pulstec Industrial Co., Ltd., Hamamatsu, Japan) or ShuttlePlex analyzer (Optical Disc Technologies, Irvine, CA, USA). Initial quality is represented by initial error rate, and post-exposure quality is represented by post-exposure error rate. For reference, the ECMA-379 standard defines a defect when the PIE8-max value exceeds 280. Higher or lower values may be selected, such as 150, 175, 200, 225, 250, 275, 300, 325, 350, or a range between any two of these values.

  The period of exposure to heat, humidity, and light is generally any period sufficient to assess the reliability of the optical medium. For example, this period can be about 24 hours, about 48 hours, about 72 hours, about 96 hours, about 120 hours, and the like. This period may be a single period, in which case the quality of the optical medium is measured twice, once before exposure to obtain the initial quality and once after exposure to obtain the final quality. Alternatively, this period may be a plurality of periods. For example, the quality of the optical medium can be measured initially, after 24 hours, after 48 hours, and after 72 hours. The measurement time interval may be shorter or longer. As an extreme example, the quality of the optical medium can be continuously measured during the period.

  High heat is generally any temperature above room temperature. Room temperature is typically about 22 ° C. (about 72 ° F.). As the temperature is increased, the deterioration of the optical medium is accelerated, and the reliability of the optical medium can be analyzed earlier. The temperature range can be about 60 ° C to about 120 ° C or about 70 ° C to about 100 ° C. Specific examples of high heat include about 60 ° C, about 70 ° C, about 80 ° C, about 90 ° C, about 100 ° C, about 110 ° C, about 120 ° C, and ranges between any two of these values. . A suitable temperature herein for polycarbonate optical media is about 80 ° C. Optical media having different substrate compositions may be more heat resistant.

  The high humidity is generally any humidity. Ambient humidity varies greatly by region and season. For example, July humidity in Houston, Texas, USA may be 95%, September humidity in Portland, Oregon may be 50%, and May humidity in Phoenix, Arizona may be 10%. As the humidity increases, the deterioration of the optical medium is accelerated, and the reliability of the optical medium can be analyzed earlier. The humidity range can be about 75% to about 100% or about 80% to about 90%. Specific examples of high humidity include about 75%, about 80%, about 85%, about 90%, about 95%, about 100%, and ranges between any two of these values. The preferred humidity herein for polycarbonate optical media is about 85%.

In general, exposure may be performed with light of any intensity. The light preferably has UVA light, UVB light, or both UVA and UVB light. This exposure is generally performed using full spectrum light designed to reproduce 5200K of sunlight. The intensity of light is generally measured in mW / cm ² units. The range of light intensity, from about 0.1 mW / cm ² ~ about 1,000 mW / cm ^2, and about 1 mW / cm ² ~ about 100 mW / cm ^2, and about such 40 mW / cm ² ~ about 60 mW / cm ² is is there. Specific examples of the light intensity of about 0.1 mW / cm ^2, about 0.5 mW / cm ^2, from about 1 mW / cm ^2, from about 5 mW / cm ^2, about 10 mW / cm ^2, about 20 mW / cm ^2, about 30mW / cm ^2, about 40 mW / cm ^2, about 50 mW / cm ^2, about 60 mW / cm ^2, about 70 mW / cm ^2, about 80 mW / cm ^2, about 90 mW / cm ^2, about 100 mW / cm ^2, about 200 mW / cm ^2, about 300 mW / cm ^2, about 400 mW / cm ^2, about 500 mW / cm ^2, about 600 mW / cm ^2, about 700 mW / cm ^2, about 800 mW / cm ^2, about 900 mW / cm ^2, about 1,000 mW / cm ² , and ranges between any two of these values. The exposure can be performed using various light sources. Examples of the light source include a lamp (lighting fixture), a metal halide lamp, an LED metal halide lamp, and an LED.

  The method further comprises comparing the initial quality and post-exposure quality of the optical medium. Ideally, the initial quality and post-exposure quality are substantially the same, which is reliable and suggests a desirable optical medium for long-term data storage. Conversely, if the post-exposure quality is substantially lower than the initial quality, or if the post-exposure error rate is substantially higher than the initial error rate, it may be unreliable and undesirable as an optical medium for long-term data storage. It is suggested. The initial quality and post-exposure quality (or initial error rate and post-exposure error rate) of the optical medium can be plotted and displayed graphically. Comparisons can be made for absolute changes (delta between initial quality and post-exposure quality) or percentage changes.

  The comparative evaluation can be performed between a plurality of different optical media. These optical media can be separated into (a) a more desirable optical medium with a small difference between initial quality and post-exposure quality, and (b) a less desirable optical medium with a large difference between initial quality and post-exposure quality. . Using quantitative target values can separate the more desirable optical media from the less desirable optical media. For example, ECMA-379 does not allow PIE8-max values above 280, but PIE8-max values below 280 are more desirable. Other numerical indicators or numbers can also be used to compare more desirable and less desirable optical media.

Method for Assessing Optical Media Quality and Consistency Another method of assessing optical media quality screens optical media and media drives to identify a combination of better and less preferred. Contrary to popular perception, not all optical media are made equally, and not all media drives are made equally. The inventors have surprisingly found that using certain combinations of optical media and media drives can result in unexpectedly good or poor quality results.

  One embodiment relates to a method for identifying suitable combinations of optical media and media drives. The method includes providing M optical media, providing N media drives, writing data to the optical media using each combination of optical media and media drives, Measuring the quality value of the optical medium after writing to obtain a total of M × N quality measurement values, and comparing the quality measurement values, wherein M is an integer of 1 or more; N may be an integer of 1 or more, and at least one of M and N may be 2 or more.

  The measurement of the post-write quality value may be any of the above-described measurements, which includes a block error rate (BLER), an internal parity error (PIE), an internal parity error 8 maximum value (PIE8 max, continuous 8). Maximum value of internal parity errors of one ECC block), internal parity error 8 average value (PIE8 average, average value of total internal parity errors of 8 consecutive ECC blocks), internal parity error 8 event (PIE8 events), PIF (Internal parity failure), PIF byte, POF (external parity failure), jitter, or a combination thereof.

  The values of M and N may be the same or different. In certain embodiments, M may be 2 or more, and N may be 2 or more. Specific examples of M include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, and the like. Specific examples of N include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, and the like.

  The method may further comprise the step of displaying the quality measurement in a graph. An example of such a graph display is shown in FIG.

  The method may further comprise selecting the combination of the optical media and media drive that yielded the optimal post-write quality value. If M is 1, this selection is to select the media drive that provides the optimal quality value with the specified optical media. If N is 1, this selection is to select the optical media that provides the optimum quality value with the specified media drive.

System for Evaluating Optical Media Another embodiment is directed to a system that can be used to implement the above-described method for evaluating optical media.

  The system includes: at least one optical medium; an analyzer that evaluates the initial writing quality or post-writing quality of the optical medium; and the post-exposure quality of the optical medium; And an environmental chamber exposed to light. The system may further comprise at least one drive device that writes data to the optical medium prior to the initial quality assessment.

  The environmental chamber is a controller unit that is programmable to provide a constant or changeable heat, a constant or changeable humidity, a constant or changeable light, and various combinations thereof. Can be connected. The environmental chamber may further include at least one meter that measures temperature, humidity, light intensity, or a combination thereof.

  The system may further comprise a graphic display device that compares the initial quality of the optical medium with the post-exposure quality of the optical medium. At present, the graphic display device is a computer capable of displaying a table, chart or graph.

  Another embodiment is directed to an environmental chamber. The chamber has a heat source, a humidity source, and a light source. This chamber is connected to a controller unit that controls the heat, humidity, and light in the chamber. The chamber is configured to simultaneously expose multiple optical media to high heat, high humidity, and light. Ideally, the chamber exposes the plurality of optical media to substantially the same heat, humidity, and light over the exposure period.

The chamber may further include a holding unit that holds the plurality of optical media. The medium may be placed at a fixed position or movably. The holding portion may include one or more spindles, clips, or other holding mechanisms configured to hold the optical medium. In a simple configuration, the holding unit arranges the plurality of optical media at substantially the same distance from the light source. In a more complicated configuration, the holding unit may include a rotating tray (rotating rack), a conveyor (conveying device), or other movable mechanism that moves the optical medium in the chamber.
Example

Test Optical Media Millenniata (M-Arc ™ Disc, Millenniata, Inc., Provo, Utah, USA), Mitsubishi (Falcon Media Pro Century Gold Architect, Lot MCC 02RG20, Mitsubishi, Japan), Verbatim (Archiv 8 , Lot 02RG20, Verbatim, Charlotte, North Carolina, USA, Delkin (Archive Gold DVD-R 100 year disc, Lot MBI 01 RG40, Delkin Devices, Inc., Poway, Calif., USA), MAM-A. Archive 8X, Lot MBI 01 RG40, MAM-A, Inc., US Kolo De State Colorado Springs), and Taiyo Yuden (DVD-R 4.7 GB, lots TYG02, was to get the disk by six each from the five companies of the manufacturer of the United States, Illinois Schaumberg).

Disc quality or error rate measurement PIE8-max, PIE8-average, PIE8-events, PI-max, and PI-average of each disc were measured using a ShuttlePlex DVD analyzer (Optical Disc Technologies, Irvine, California, USA). Measured at various periods. Values were graphed on an Apple Macintosh MacBook Pro computer using common spreadsheet and graphing software.

The environmental chamber test used a model FRC-27F temperature and humidity chamber (Blue M. location). This chamber was equipped with a light source. A holding unit was used to place the optical disk on a spindle maintained at 27 to 30 cm from the light source.

The light source was a pair of UHI-150DD / UVP Euroflood ™ UHI series 150 watt, 95 volt small metal halide lamps (color temperature 5200K, luminous flux 11000 lm, Usio America, Cypress, Calif., USA). The light intensity at the disc was measured as 43 mW / cm ^{2 to} 53 mW / cm ² .

  The chamber interior is a programmable temperature and humidity controller unit, JC Systems 600-RTD (TMC Services, Inc., Elk River, MN, USA).

Exposure conditions The reliability of various optical disks was evaluated using the following test profiles.

  The following tables show the error rate measurements for the various discs, initial and post exposure. Measurements were taken before initial exposure, 24 hours after exposure, and 48 hours after exposure. In these tables, AR refers to a Millennial disk, MI refers to a Mitsubishi disk, VE refers to a Verbatim disk, DE refers to a Delkin disk, and MA refers to a MAM-A disk.

  The results of Table 2 for PIE8-max are shown graphically in FIG. Millenniata PIE8-max values remained largely unchanged upon exposure to heat, humidity, and light. The Mitsubishi and Verbatim discs had relatively low initial PIE8-max values, but the PIE8-max values after 48 hours exposure were significantly increased. In the case of Delkin and MAM-A discs, the initial PIE8-max value was comparable to the Millennia disc, but the PIE8-max value increased significantly after both 24 and 48 hours of exposure.

  The results in Table 3 for PIE8-average are shown graphically in FIG. Millenniata PIE8-average values remained largely unchanged upon exposure to heat, humidity, and light, and in fact, in some cases decreased. Mitsubishi and Verbatim discs had relatively low initial PIE8-average values, but PIE8-average values after 48 hours exposure were significantly increased. In the case of Delkin and MAM-A discs, the initial PIE8-average value was comparable to the Millennia disc, but the PIE8-average value was significantly increased after both 24 and 48 hours of exposure.

  The results of Table 4 for PIE8-events are shown graphically in FIG. Arbitrary PIE8-events value 5,000 is given to the unreadable disc. Millenniata PIE8-events values are largely unchanged or reduced upon exposure to heat, humidity, and light. In one case, the Millennia disk PIE8-events value went from zero to 151. All Mitsubishi and Verbatim discs had zero initial PIE8-events values, but PIE8-events values after 48 hours exposure were significantly higher. In the case of Delkin and MAM-A discs, the initial PIE8-events values were similar to the Millennia discs, but the PIE8-events values were significantly increased after both 24 and 48 hours exposure.

  The results of Table 5 for PIE-max are shown graphically in FIG. Millennia disc PIE-max values remained largely unchanged upon exposure to heat, humidity, and light. The Mitsubishi and Verbatim discs had relatively low initial PIE-max values, but the PIE-max values after 48 hours exposure were significantly increased. In the case of Delkin and MAM-A discs, the initial PIE-max value was similar to that of the Millennia disc, but the PIE-max value increased significantly after both 24 and 48 hours of exposure.

The results in Table 6 for PIE-average are shown graphically in FIG. Millenniata PIE-average values were largely unchanged or slightly decreased upon exposure to heat, humidity, and light. Mitsubishi and Verbatim discs had relatively low initial PIE-average values, but PIE-average values after 48 hours exposure were significantly increased. In the case of Delkin and MAM-A discs, the initial PIE-average value was similar to the Millennia disc, but the PIE-average value was significantly increased after both 24 and 48 hours of exposure.

Evaluation of optical media and media drive combinations For evaluation, five manufacturers of optical media DVD disks (Delkin, MAM-A, Mitsubishi, Taiyo Yuden, and Verbatim) and three manufacturers of optical media disk drives ( Pioneer, Optiarc, and NEC (NEC) were selected. In the test, three disks were used for each manufacturer, and the quality values of each were averaged. The Pioneer DVD drive was model number DVR-116A (Pioneer, Tokyo, Japan). The Optiarc DVD drive was model number AD 5170A (Sony Optiarc Corporation, Tokyo, Japan). The NEC DVD drive was model number ND-3550A (NEC Corporation, Santa Clara, California, USA).

  Each disk was written with a 400 MB data file using the drive. The quality of the data file was evaluated using PIE8-max obtained from a ShuttlePlex DVD analyzer (Optical Disc Technologies, Irvine, CA, USA). A total of 15 values were obtained (the number of 5 disk manufacturers is multiplied by the number of 3 drive manufacturers. Each disk value is the average of 3 disks). The obtained PIE8-max values are shown in the following table.

  The various values are displayed in a graph on an Apple Macintosh MacBook Pro computer using a general spreadsheet and graphing software, and are shown in FIG. The optimal combination of optical media and media drive shows the lowest PIE8-max value. In this case, the combination of Mitsubishi disk and NEC drive was optimal at a value of 20.8.

Summary From the above examples, it was proved that the judgment on the quality of the media can be made quickly. After only 48 hours of testing, it was found that certain media showed significant worsening of PIE compared to other media that showed little or no worsening of PIE. This provides an effective comparative index not only for media data retention when exposed to extreme conditions, but also for data retention period lengths expected in room temperature, humidity, and light conditions.

  When an initial PIE assessment is performed and compared to PIE after simultaneous exposure to high heat, high humidity, and intense light, it is possible to predict the expected data retention time under normal conditions. Based on this, it can be concluded that Millennia's medium is expected to retain significantly longer data than other media. This determination was obtained after a relatively short 48 hour comparative test. Given the fact that traditional tests require weeks to obtain data retention results that show this difference between high and low quality media, the tests in this specification are in contrast to conventional tests. is there.

  All configurations and / or methods and / or steps and / or equipment disclosed and claimed herein can be made and executed without undue experimentation by reference to the present disclosure. The configuration and method of the present invention have been described above. However, those skilled in the art will understand the above configuration and / or method and / or process and / or device, and the present specification without departing from the concept and scope of the present invention. It will be clearly understood that various variations may be applied to the method steps or series of steps described in the document. More specifically, it is clearly understood that the same or similar results can be achieved if specific agents, both chemically and physically related, are used in place of the agents described herein. Will be done. All such similar substitutes and modifications that are apparent to those skilled in the art are deemed to be within the scope of the present invention.

Claims (20)

A method for evaluating the reliability of an optical medium,
Evaluating the initial quality of the optical medium;
Exposing the optical medium to high heat, high humidity, and light simultaneously for a period of time;
Evaluating the post-exposure quality of the optical medium.   2. The method of claim 1, wherein the optical medium is a CD disc, a DVD disc, or a Blu-ray disc.   2. The method of claim 1, wherein the steps of evaluating the initial quality and the post-exposure quality include a block error rate (BLER), an internal parity error (PIE), and an internal parity error 8 maximum value. (PIE8 max, maximum value of total internal parity errors of eight consecutive ECC blocks), internal parity error 8 average value (PIE8 average, average value of total internal parity errors of eight consecutive ECC blocks), internal parity error 8 Events (PIE8 events), PIF (parity inner failures, internal parity failures), PIF bytes, POF (parity outer failures, external parity failures), jitter, or these A method comprising the step of measuring a combination. The method of claim 1, wherein the high heat is about 60 ° C to about 120 ° C, the high humidity is about 75% to about 100%, and the light intensity is about 0.1 mW / cm ² to about 1. , 000 mW / cm ² . The method of claim 1, wherein the high heat is about 80 ° C., the high humidity is about 85%, the intensity of the light is about 40 mW / cm ² ~ about 60 mW / cm ² method.   2. The method of claim 1, wherein the light comprises UVA light, UVB light, or both UVA light and UVB light.   The method of claim 1, wherein the period of time is from about 24 hours to about 120 hours. The method of claim 1, wherein the method comprises:
A method comprising the step of measuring the post-exposure quality over a plurality of periods. The method of claim 1, wherein the method comprises:
A method comprising a step of continuously measuring the post-exposure quality during the exposure step. The method of claim 1, further comprising:
Comparing the initial quality and the post-exposure quality. A method for evaluating a combination of an optical medium and a medium drive,
Providing M optical media;
Providing N media drives;
Writing data to the optical medium using each combination of optical medium and medium drive;
Measuring the quality value of each of the optical media after the writing step to obtain a total of M × N quality measurement values;
Comparing the quality measurements, comprising:
M is an integer of 1 or more,
N is an integer of 1 or more,
Comparing at least one of M and N with two or more said quality measurements.   12. The method according to claim 11, wherein the step of evaluating the quality after the writing step includes block error rate (BLER), internal parity error (PIE), internal parity error 8 maximum value (PIE8 max, eight consecutive ECC blocks). Internal parity error total maximum), internal parity error 8 average value (PIE8 average, average value of total internal parity errors of 8 consecutive ECC blocks), internal parity error 8 event (PIE8 events), PIF (internal parity) Failure), PIF byte, POF (external parity failure), jitter, or a combination thereof.   12. The method of claim 11, wherein M is 2 or more and N is 2 or more. A system for evaluating the reliability of optical media,
At least one optical medium;
An analyzer for evaluating the initial quality of the optical medium and the post-exposure quality of the optical medium;
And an environmental chamber that simultaneously exposes the optical medium to high heat, high humidity, and light. The system of claim 14, further comprising:
A system comprising a graphic display device for comparing the initial quality of the optical medium and the post-exposure quality of the optical medium. 15. The system of claim 14, wherein the environmental chamber is
A heat source,
A humidity source;
A light source and a controller that controls the heat, humidity, and light in the chamber;
A holding unit for holding a plurality of optical media,
The chamber is configured to simultaneously expose the plurality of optical media to high heat, high humidity, and light.   The system according to claim 16, wherein the medium is disposed at a fixed position in the chamber.   The system according to claim 16, wherein the medium is movably arranged in the chamber.   The system according to claim 16, wherein the holding unit holds the plurality of optical media at a substantially equal distance from the light source.   The system according to claim 16, wherein the holding unit includes a rotating tray or a conveyor.

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